body {
    background: #f5f7fa;
    color: #1f2937;
}

.app-layout {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 260px;
    background: #111827;
    color: #fff;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 24px 18px;
}

.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 10px;
}

.sidebar-brand h2 {
    margin: 0;
    font-size: 22px;
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 30px;
}

.sidebar-nav a {
    color: #d1d5db;
    text-decoration: none;
    padding: 12px 14px;
    border-radius: 10px;
}

.sidebar-nav a.active,
.sidebar-nav a:hover {
    background: #1f2937;
    color: #fff;
}

.sidebar-footer {
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding-top: 16px;
    margin-top: 30px;
}

.main-content {
    flex: 1;
    padding: 28px;
}

.page-header {
    margin-bottom: 24px;
}

.card,
.content-box {
    background: #fff;
    border-radius: 16px;
    padding: 20px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.05);
}

.cards-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
    margin-bottom: 24px;
}

.login-page {
    display: grid;
    place-items: center;
    min-height: 100vh;
}

.login-box {
    width: min(420px, 90vw);
    padding: 28px;
    border-radius: 16px;
    background: #fff;
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.08);
}

.login-box h1 {
    margin-bottom: 20px;
}

@media (max-width: 900px) {
    .app-layout {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
    }

    .cards-grid {
        grid-template-columns: 1fr 1fr;
    }
}